Fairy rings -- mushrooms that grow in a circle in the lawn -- aren't created by fairies, but by a group of fungi known as basidiomycetes. Fungi is present in the lawn due to nutrients, such as a submerged tree trunk, on which it feeds. The ring can grow from a few to hundreds of feet in diameter over several years. The main part of the fungus isn't the mushroom on the surface, but a buried mass known as mycelium. Although you can knock down the mushrooms, they will return because of the underground structure. Purdue University Extension scientists say there is no controlling fairy ring. Your choices are to dig up the offending ring or make the ring less visible with proper lawn care.
Core aerate the lawn, going over the entire surface twice. Start aerating 2 feet away from the ring and work your way inward to the middle of it. This helps break up fungal masses on the surface and allows water and fertilizer to penetrate to the grass' roots. Remove the cores from the lawn. When finished, water the lawn as you normally do.
Fertilize the lawn on a regular schedule. An easy way to remember when to fertilize is to build your schedule around major holidays: Memorial Day weekend, July fourth and Labor Day weekend.
Remove the fairy ring if you don't want to mask it by digging up the turf. Begin 18 inches away from the outside edge of the ring and including the entire ring. Discard the turf and dig into the infected soil until you've removed the entire fungal mass. Discard the soil and fill the area with fresh soil. Reseed the lawn.
Things You Will Need
- Core aerator
- Research projects are underway to find a suitable fungicide for the control of fairy ring. Consult your county cooperative extension agent to determine if there are new fungicides on the market.
- Agweek; Getting Rid of Fairy Rings Requires Patience; Ron Smith; May 2010
- Purdue Extension; Fairy Rings in Lawns/Dark Green Circles in Lawn; Peggy Sellers, et al.; March 2011
- University of California: Mushrooms and Other Nuisance Fungi in Lawns;M. Le Strange, et al.; January 2008
- Lawn and Mower: Fairy Rings -- Fungal Lawn Disease